1. Field of the Invention
The invention relates to a length of textile, especially as a basis for paper-making machine coverings, the length of textile containing structural threads and, viewed width-wise, being composed at least in part of several partial lengths which are located next to one another and which are bonded to one another on their edges. It relates furthermore to a process for producing one such textile length.
2. Description of the Related Art
Textile lengths of this type are used first of all for transport of paper webs through a paper-making machine (GB-A-975 750; EP-A-0 665 329; EP-B-0 464 258). Viewed width-wise they are composed of partial lengths, with a width which is much less than the final width of the textile length. The partial lengths extend essentially in the longitudinal direction of the textile length and are formed by one or more partial length strips having been continuously wound in the lengthwise direction of the textile length and helically transversely thereto.
In one version the partial lengths consist of structural threads, for example in the form of a fabric. In other versions the structural threads form a carrier on which a nonwoven is needled on one or both sides so that the textile length forms a felt. These felts are suitable especially for guiding the paper webs in the press part of a paper-making machine.
In the textile lengths known previously the individual partial lengths are wound not only to overlap, but also with their edges next to one another. To obtain sufficient transverse stability, the edges of the lengths are joined to one another. For this reason it is suggested that the edges of the lengths be sewn, melted or bonded, for example with ultrasonic bonding (EP-A-0 665 329). Alternatively it is provided that the edges of the lengths be provided with seam loops and a connection established using an insert wire through the seam loops.
In the known solutions for connecting the edges of the partial lengths, it is disadvantageous that the structure of the textile length in the connection area deviates greatly from the other areas so that for example the permeability of the textile length is changed; this can have an adverse effect for use of the textile length in a paper-making machine on the quality of the paper web. This is especially the case when the edges of the lengths are sewn to one another. The sewing thread represents an outside material which changes the nature of the product. In addition, the displacement strength is unsatisfactory. In addition, some of the proposals for joining the edges of the lengths are very labor intensive.